Hydraulic change-speed mechanism



July 5, 1932. jl NET-TEL HYDRAULIC CHANGE SPEED MECHANISM Filed June 27, 1929 4 Sheets-Sheet l July 5, 1932. J, NETTEL 1,866,266

HYDRAULIC CHANGE SPEED MECHANISM Filed June 27, 1929 4 Sheets-Sheet 2 July-5, 1932. J. NETTEL HYDRAULIC CHANGE SPEED MECHANISM Filed June 27, 1929 July l5, 1932. J, NETTEL 1,866,266

HYDRAULIC CHANGE SPEED MECHANISM Filed June 27, 1929- 4 Sheets-Sheet 4 Patented `luly 5, 1932 T FFlCE PAT 1 JIt NETTEL, OF PRAGUE, CZECHOSLOVAKIA HYDRAULIC CHANGE-SPEED MECHANISM Application led June 27, 1929, Serial N'o. 374,180, and in Czechoslovakia April 29, 1929.

This invention relates to a hydraulic change-speed mechanism for motor vehicles and the like and'of the kind wherein the power is transmitted from a driving to a driven shaft by means of a liquid when a passage between two cylinders wherein pistons controlled by one of the shafts, is more or less closed, and the invention consists essentially in the provision of pistons in the form of o plates which are mounted by means of aperturesv on the cranks of the driven shaft. The elements whereby the passages are closed vconsist of rotary valves which are operated by means of a lever, the latter being also adapt- 15 ed, during part of its movement, to operate the principal brakes. Means are provided, in conjunction with anvadditional brake, for a reversal of the transmitted motion.

Fig. l of the accompanying drawings is a 20 perspective sectional view of the mechanism,

Fig. 2 is a longitudinal section thereof, Fig. 3 is a` section on the line III-.IH of Fig. 2, Y

Fig. 4 is a section on the line IV-IV of i5 Fig. 2,

Fig. 5 is a section on the line V-V of Fig. 2, Fig. 6 is a section on the line VI-VI of Fig. 2, 30 Fig. 7 represents a plan and a longitudinal section of one of the pistons,

Fig. 8 is a front view of the valve control, and

Fig. 9 is a longitudinal section of one of the 35 controlling elements.

The motor shaft l of the vehicle carries a casing 3 which also serves as a fly-wheel and which is formed with flat, straight, radin al passages 4 which communicate in pairs at the outer ends. Diametrically opposite passages are aligned for the accommodation of a plate 5 adapted to serve in each passage as a piston for driving the liquid, such as oil or the like, from one passage of a pair into the other. The plates are provided with centrally disposed transverse apertures whereby they are mounted, by means of bearing sleeves 7, on the cranks of a clutch shaft 2. There are in the present instance two diametrically opposite cranks, and each crank controls two plates 5 arranged at right angles to each other. The plates operating in two communicating passages are controlled by different cranks so that one moves outwards when the other moves inwards.

The comfifi munication between each pair o-f passages is f regulated by means of a rotary valve 6 which, when open, leaves the liquid perfectly free to pass from one passage into the other, so that the casing can rotate freely without affecting the'orank shaft 2.

"RV hen the valves are closed so as to prevent the liquid from flowing from one passage mto the other, the plates will be prevented from moving, and

`the shaft 2 will be compelled to participate at full speed in the moven'ient of the shaft 1. Vith the valves in intermediate positions the communication will be more or less restricted, and motion will be transmitted to the shaft 2 in inverse proportion to the escape of liquid. P

The valves are controlled by arms 32, and the arms of two adjacent valves engage 1n slots in a nut 3l which is mounted on a worm to rotate together with the latter.

The sleeve 27 projects through the sleeve 25, and both sleeves are provided with keys whereby they engage a collar 8 which thus communicates rotation from one sleeve to the other while it is 'capable of axial displacement relative to both.

Another collar 26, which is rotatable but not slidable relative to the collar 8, is engaged by a lever 14 whereby the collar 8 can thus be displaced a-Xially on the sleeves. The'keys whereby one of the sleeves engages the collar 8 are partly helical so that the movements imparted to the collar by the lever 14 in the forward direction from its central position, causes the sectors 9 to turn relative to the casing 3 for closing the valves 6. Part of the keys are parallel with the sleeve axis, however, so that if the lever be turned backwards from its central position, no adiso rf reverse direction.

the central position of the lever 14 the valves are open, and the shaft 2 is therefore disconnected from the shaft 1 This condition will be maintained While the lever 14 is turned backwards from its central position, and this part of the lever movement can therefore be utilized for the application of the principal brakes of the vehicle, the lever being for this purpose adapted to operate a shaft 13.

To compensate for leakage o f liquid, the different passages are connected by means of ducts 11 to the pressure pump of the lubrieating system. Air can be exhausted from the passages through apertures fitted with detachable screw caps or plugs 12.

The clutch shaft 2 enters the holloW p0rtion of the propeller or cardan shaft 21 relativeto which it is rotatable. A clutch element 18, which is slid-.ably feathered on the shaft 21, is formed at one end With claws adapted, under the iniiuence of a spring 22, to engage bet-Ween claws formed on a conical gear 17 secured to the shaft 2, the tivo shafts being in this manner normally coupled together. Another conical gear 19, which is slidably feathered on the clutch element, supports the spring 22 and is itself supported by a brake drum 16 Which encloses the tivo gears and which carries a conical pinion 23 arrangec so as to mesh with both gears 17, 19. Brake blocks 15, which are operated by means of screw spindles 28, gears 29 and a lever 20, are 'adapted to be applied to the brake drum and act normally as a secondary brake. The clutch element 18 can be disengaged from the gear 17 by means of a lever 24. The shafts being thus disconnected, the shaft 21 stops and causes the pinion 23 to roll about the gear 19 as to impart motion to the ff brake drum at half the speed of the shaft 2.

If no-W the brake blocks are applied to the drum so as to stop the latter, the motion of the shaft 2 Will be transmitted tothe shaft 21 through the medium of the pinion 23 in the The reversing` speed can be regulated as before by means of the hydraulic clutch. and the principal brakes can be applied as usual by means of the lever 14 during the backward movement.

The employment of double-ended plates as a substitute for the usual cylindrical pistons, has the advantage that a considerable reduction in the size and Weight of the clutch casing and in the length of the passages Will be obtained. he passages, When opened, will be uniform throughout so that friction will be reduced to a minimum. By connecting tWo valves to each controlling shaft, a simplification of the mechanism is effected. The control of the vehicle is considerably simplified so that all the different stages from maX- imum to minimum transmission ratio and from minimum to maximum braking effect can be carried out by a movement of the control lever from one end position t0 another.

By the employment of the auxiliary brake as a means for effecting reversing movement, economy of constructional parts is obtained.

I claim:

1. A hydraulic change-speed mechanism of the character described comprising a driving shaft, a casing on said shaft having radial passages which communicate in pairs at their outer ends, a driven shaft having diametrically opposite cranks disposed Within the casing, pairs of straight rectangular plates mounted on the cranks by means of centrally disposed transverse apertures, each plate guided in two diametrically opposite passages and adapted to drive liquid from one passage into another of a pair on arelative rotation of the cranks and the casing, and means for restricting the communication between the passages so as to oppose the movenent of the liquid and relative rotation of the tWo shafts.

2. A structure as claimed in claim 1 Wherein each crank controls tWo plates arranged at right angles to each other.

3. A structure as claimed in claim 1 Wherein vthe passages and plates are normally of uniform cross-sectional area throughout their lengths. f

4:. A structure as claimed in claim 1 Wherein the means for restricting the communication between the passages comprise rotar;r valves and operating shafts each of Which acts on two adjacent valves.

.nur NETTEL. 

